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All 12 Flashcards — What is a species?
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Question
Define a species.
Answer
A group of organisms that can **interbreed** and produce **fertile offspring**.
Question
What is the biological species concept?
Answer
Defining a species by the ability to **interbreed** and produce **fertile offspring**.
Question
What does 'fertile offspring' mean?
Answer
Young that are themselves **able to reproduce**.
Question
What is a hybrid?
Answer
The offspring of a cross between **two different species** (e.g. a mule).
Question
What does 'sterile' mean?
Answer
**Unable to reproduce** — cannot produce offspring of its own.
Question
Are a horse and a donkey the same species? Why?
Answer
**No** — they produce a **mule**, which is **sterile**, so they are different species.
Question
Why is 'they can breed' not a full definition of species?
Answer
It leaves out that the offspring must be **fertile** — sterile young mean the parents are different species.
Question
Are two very different dog breeds the same species?
Answer
**Yes** — they can interbreed and give fertile pups; breed differences are just variation within one species.
Question
What is a karyotype?
Answer
An organism's full set of **chromosomes**, shown by their **number, size and shape**.
Question
How can karyotyping help decide if two organisms are the same species?
Answer
**Matching** chromosome number/pattern supports the **same** species; clearly **different** karyotypes suggest different species.
Question
Name two cases where the biological species concept is hard to apply.
Answer
Organisms that **do not reproduce sexually** (e.g. bacteria) and **fossils**.
Question
What is the offspring of a horse and a donkey called?
Answer
A **mule** — a sterile **hybrid**.
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Full study notes for What is a species?
Topic 1.6 hub
Diversity of organisms
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Biology exam skills
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